step 2 complete: all request/response models defined and validated

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

BACKEND_PLAN.md

@@ -98,8 +98,8 @@ adiuva-api/
 - [x] Write `.env.example`
 - **Outcome:** Runnable FastAPI skeleton (returns 404 on all routes).
 
-### Step 2 — Pydantic schemas (API contracts)
-- [ ] Create `app/schemas.py` (mirrors `src/shared/api-types.ts` from Electron repo):
+### Step 2 — Pydantic schemas (API contracts) ✅
+- [x] Create `app/schemas.py` (mirrors `src/shared/api-types.ts` from Electron repo):
   - `ChatRequest`: `message: str`, `context: ChatContext`, `execution_mode: Literal['direct', 'plan']`
   - `ChatContext`: `user_profile: dict`, `relevant_documents: list[str]`, `recent_tasks: list[dict]`, `conversation_history: list[dict]`
   - `ChatResponse`: `response: str`, `actions: list[PlanAction]`

app/schemas.py

@@ -0,0 +1,84 @@
+"""Pydantic schemas — API request/response contracts.
+
+Mirrors the TypeScript types from the Electron app (src/shared/api-types.ts).
+"""
+
+from __future__ import annotations
+
+from typing import Any, Literal
+
+from pydantic import BaseModel, Field
+
+
+# ── Billing ──────────────────────────────────────────────────────────
+
+BillingTier = Literal["free", "pro", "power", "team"]
+
+
+# ── Auth ─────────────────────────────────────────────────────────────
+
+class AuthTokens(BaseModel):
+    access_token: str
+    refresh_token: str
+    expires_at: int
+
+
+class UserProfile(BaseModel):
+    id: str
+    email: str
+    tier: BillingTier
+
+
+# ── Chat ─────────────────────────────────────────────────────────────
+
+class ChatContext(BaseModel):
+    user_profile: dict[str, Any] = Field(default_factory=dict)
+    relevant_documents: list[str] = Field(default_factory=list)
+    recent_tasks: list[dict[str, Any]] = Field(default_factory=list)
+    conversation_history: list[dict[str, Any]] = Field(default_factory=list)
+
+
+class PlanAction(BaseModel):
+    type: Literal[
+        "create_record",
+        "update_record",
+        "delete_record",
+        "index_document",
+        "send_notification",
+    ]
+    table: str | None = None
+    data: dict[str, Any] | None = None
+
+
+class ChatRequest(BaseModel):
+    message: str
+    context: ChatContext = Field(default_factory=ChatContext)
+    execution_mode: Literal["direct", "plan"] = "direct"
+
+
+class ChatResponse(BaseModel):
+    response: str
+    actions: list[PlanAction] = Field(default_factory=list)
+
+
+# ── Execution Plans ──────────────────────────────────────────────────
+
+class PlanStep(BaseModel):
+    action: str
+    prompt_template: str | None = None
+    variables: dict[str, Any] | None = None
+    data_from_step: int | None = None
+
+
+class ExecutionPlan(BaseModel):
+    agent: str
+    steps: list[PlanStep] = Field(default_factory=list)
+
+
+# ── Backup ───────────────────────────────────────────────────────────
+
+class BackupMetadata(BaseModel):
+    version: int
+    timestamp: int
+    checksum: str
+    chunk_count: int